op {
  graph_op_name: "AssignSub"
  in_arg {
    name: "ref"
    description: <<END
Should be from a `Variable` node.
END
  }
  in_arg {
    name: "value"
    description: <<END
The value to be subtracted to the variable.
END
  }
  out_arg {
    name: "output_ref"
    description: <<END
= Same as "ref".  Returned as a convenience for operations that want
to use the new value after the variable has been updated.
END
  }
  attr {
    name: "use_locking"
    description: <<END
If True, the subtraction will be protected by a lock;
otherwise the behavior is undefined, but may exhibit less contention.
END
  }
  summary: "Update \'ref\' by subtracting \'value\' from it."
  description: <<END
This operation outputs "ref" after the update is done.
This makes it easier to chain operations that need to use the reset value.
END
}
